n-api: change napi_callback to return napi_value

Change `napi_callback` to return `napi_value` directly instead of
requiring `napi_set_return_value`.

When we invoke the callback, we will check the return value and
call `SetReturnValue` ourselves. If the callback returns `NULL`,
we don't set the return value in v8 which would have the same
effect as previously if the callback didn't call
`napi_set_return_value`. Seems to be a more natural way
to handle return values from callbacks. As a consequence,
remove `napi_set_return_value`.

Add a `napi_value` to `napi_property_descriptor` to support string
values which couldn't be passed in the `utf8name` parameter or
symbols as property names. Class names, however, cannot be symbols
so this `napi_value` must be a string type in that case.

Remove all of the `napi_callback_info` helpers except for
`napi_get_cb_info` and make all the parameters to
`napi_get_cb_info` optional except for argc.

Update all the test collateral according to these changes.
Also add `test/addons-napi/common.h` to house some common macros
for wrapping N-API calls and error handling.

PR-URL: https://github.com/nodejs/node/pull/12248
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>

1 files changed, 9 insertions, 13 deletions

diff --git a/test/addons-napi/1_hello_world/binding.c b/test/addons-napi/1_hello_world/binding.c
index 882508b9548..57bac37fa0b 100644
--- a/test/addons-napi/1_hello_world/binding.c
+++ b/test/addons-napi/1_hello_world/binding.c
@@ -1,22 +1,18 @@
 #include <node_api.h>
+#include "../common.h"
+#include <string.h>
 
-void Method(napi_env env, napi_callback_info info) {
-  napi_status status;
+napi_value Method(napi_env env, napi_callback_info info) {
   napi_value world;
-  status = napi_create_string_utf8(env, "world", -1, &world);
-  if (status != napi_ok) return;
-  status = napi_set_return_value(env, info, world);
-  if (status != napi_ok) return;
+  const char* str = "world";
+  size_t str_len = strlen(str);
+  NAPI_CALL(env, napi_create_string_utf8(env, str, str_len, &world));
+  return world;
 }
 
-#define DECLARE_NAPI_METHOD(name, func)                          \
-  { name, func, 0, 0, 0, napi_default, 0 }
-
 void Init(napi_env env, napi_value exports, napi_value module, void* priv) {
-  napi_status status;
-  napi_property_descriptor desc = DECLARE_NAPI_METHOD("hello", Method);
-  status = napi_define_properties(env, exports, 1, &desc);
-  if (status != napi_ok) return;
+  napi_property_descriptor desc = DECLARE_NAPI_PROPERTY("hello", Method);
+  NAPI_CALL_RETURN_VOID(env, napi_define_properties(env, exports, 1, &desc));
 }
 
 NAPI_MODULE(addon, Init)